The present invention generally relates to the field of wireless communications, and more particularly to a transceiver having improved receiver architecture.
There are many applications in which it is desirable to be able to provide wireless communications. For example, in an industrial warehouse environment individual roaming workers may utilize portable data terminals for inventory tracking and accounting purposes. The warehouse worker must be mobile, having the freedom of movement throughout any position in the warehouse to reach the product location, yet remain in constant communication with a central or host computer over a local network. In such an application, it is desirable for the mobile data terminal to communicate with the host computer over the central network via wireless communications, for example by using a radio-frequency transceiver. Thus, an interface device, or access point, may be utilized to serve as an interface between a wireless and a directly linked communication network.
It is often desirable for a network interface device to utilize several forms of communications media. For example, it may be desirable to provide an access point interface to utilize two individual radio-frequency transceivers for providing communications at two different frequencies simultaneously. Such a transceiver may transmit on a first frequency and receive on a second frequency in order to provide full duplex communications, avoid interference, etc.
A communication transceiver typically requires or preferably utilizes duplex communications wherein information is both transmitted and received by a single unit transceiver unit and wherein the transmitter apparatus and receiver apparatus of the transceiver share common hardware and resources. In such a transceiver, selection between the transmitter and receiver is implemented via switching and electronic enabling of the required hardware devices. However, because of the loading and cross talk effects caused by the sharing of common hardware and from the use of switches, increased noise may be introduced into the communication signal, the signal-to-noise ratio may decreased and the noise figure of the signal may be increased correspondingly. Lower signal-to-noise ratios adversely affect maximum transmission ranges and increased noise figures result in an increase in transmission error rates because of maximum power limits mandated by government regulations and other design constraints.